Correlation Between Serum Insulin-like Growth Factor-1 Level And Cognitive Function In Patients With Bipolar Disorder

Background:Bipolar disorder,is a common,chronic,episodic mood disorder that is one of the leading causes of disability worldwide.The pathogenesis of bipolar disorder is unclear,more and more studies have found that the disease may be associated with neural immune and endocrine imbalance.Many studies have found that cognitive dysfunction is one of the main symptoms of bipolar disorder,Serum insulin-like growth factor-1(IGF-1)may be a mediator of cognitive impairment involved in bipolar disorder.Therefore,it is of great significance to explore the relationship between IGF-1 and the pathogenesis of bipolar disorder and its relationship with cognitive function.Objective:To detect the cognitive function and serum IGF-1 level in patients with bipolar disorder in stable period,analyze its correlation with the cognitive function of patients with bipolar disorder,and preliminarily discuss the role of IGF-1 in the pathogenesis of bipolar disorder.Methods:The subjects of this study were 40 patients with bipolar disorder in stable period who were recruited by our hospital.40 healthy adults,matched in age,sex and education,were recruited as the control group.The Hamilton Depression Rating Scale-17(HAMD-17)and Young’s Mania Rating Scale(YMRS)were used to evaluate the symptoms of depression and mania in the study group.The severity of the disease was assessed using the Clinical General Impression Scale(CGI-S).Cognitive function was assessed using Tail Making Test A(TMTA),Symbol Coding(SC),Hopkins Verbal Learning Test-Revised(HVLT-R),Brief Visuospafial Memory Test-revised(BVMT-R),Stroop Color Word Test(SCWT),and Continous Performance TestIdentical Pair(CPT-PI).Enzyme-linked immunosorbent assay(ELISA)was used to determine serum IGF-1 level.The differences in cognitive function and serum IGF-1levels between the study group and the control group were analyzed by independent sample t test.Spearman correlation analysis was used to analyze the correlation between serum IGF-1 level,cognitive function scores and Young’s Mania Scale score,Hamilton’s Depression Scale score and clinical total impression score in the study group.Spearman correlation analysis was used to analyze the correlation between serum IGF-1 level and cognitive function test results in the two groups.Results:1.The cognitive function scores of the two groups showed: the symbol coding test,simple visual memory,continuous operation test and stroop color word test scores of the study group were significantly lower than those of the control group(P<0.01);the Hopkins Word Learning Test scores were statistically different between the two groups(P<0.05);there was no statistical difference in the completion time of tail making test A between the study group and control group(P>0.05).2.Comparison of serum IGF-1 levels between the two groups: the level of serum IGF-1 in the study group(241.75±83.36ng/ml)was higher than that in the control group(167.54±77.95ng/ml),and there was statistically significant difference between the two groups(t=4.112,P <0.01).IGF-1 concentration has reference values,which are dependent on the age.Taking into account these values,35% of bipolar patients had increased IGF-1 serum concentrations,while only 5% of control subjects are above normal range.3.Correlation analysis: in the study group,serum IGF-1 level and cognitive function scores were not significantly correlated with Young’s Mania Scale,Hamilton’s Depression Scale,and clinical overall impression score(P > 0.05).4.Correlation analysis between serum IGF-1 levels and cognitive function in the control group showed that:serum IGF-1 levels in the control group were inversely correlated with completion time of the tail making test A(r=-0.338,P<0.05),were positively correlated with symbol coding score(r=0.470,P<0.05),were positively correlated with Hopkins word learning score(r=0.394,P<0.05),were positively correlated with simple visual memory score(r=0.612,P<0.05),were positively correlated with the scores of continuous operation test(r=0.372,P<0.05).5.Correlation analysis between serum IGF-1 levels and cognitive function in the study group showed that:serum IGF-1 levels in the study group were positively correlated with symbol coding scores(r=0.461,P<0.05),were positively correlated with the scores of continuous performance test(r=0.417,P<0.05),were negatively correlated with simple visual memory score(r=-0.362,P<0.05).Conclusion:1.Patients with bipolar disorder in stable period also have cognitive impairment,including decreased information processing speed,word learning,attention/alertness,visual learning,and working memory.2.The level of serum IGF-1 in patients with bipolar disorder in stable period is higher than that in healthy people,and IGF-1 may be related to the pathophysiolo-gical mechanism of bipolar disorder.3.Serum IGF-1 level was positively correlated with information processing speed and attention/alertness,and negatively correlated with visual memory in patients with bipolar in stable period,suggesting that changes in serum IGF-1 level may have an impact on cognitive function.